In many situations, and particularly in medical and dental chair situations, chairs are provided with a back and a headrest which projects above the back. Attempts have been made to produce a comfortable and easily adjusted headrest, but for the most part these have not provided the range of adjustability and ease of use that may be desired.
The headrest often is a somewhat pillow-shaped element spaced from the upper edge of the chair back and needs to be positioned to comfortably cradle the user's head. The comfort and adaptability of the headrest will be determined in great part by its angular position relative to the chair back, its position relative to the plane of the support surface of the chair back, and its distance from the top of the chair back. Each of these may require different positioning due to the characteristics of the user.
Many conventional headrests on chairs, such as dental chairs, are mounted on the chair back through mechanism which provides some degree of adjustability. However, the adjustment may require loosening of a screw-actuated mechanism, adjusting the headrest, and then having to screw the mechanism back to a tightened condition. This often is a two-handed operation and requires more operator time and effort than is desired.
A more desirable mechanism would allow the headrest to be locked in a desired position with the mechanism at rest, be able to be released by a single-hand actuation, with release of the actuator then returning the mechanism to a lock-up condition.
Further, for matters of hygiene, a plastic bag, or other covering, often is placed over the headrest and actuator mechanism making it difficult to access screw actuators or other conventional adjustment mechanism. Thus, a mechanism which permits one-handed adjustment and which may be easily operated through such a covering would be desirable.
Further, it is desirable to have a headrest support and adjustment mechanism which permits at least two degrees of pivotal freedom. Such would allow the mechanism to be pivoted, or rotated, fore-and-aft relative to the chair back, and then have another adjustment permitting pivoting of the headrest itself relative to remainder portions of the mechanism.
In the past, the height adjustment of the headrest above the chair back generally has been permitted only through a major operating stem which is slidable relative to the chair back and then frictionally held in position. There has been little opportunity for minor adjustment of the height of the headrest once the stem is held in place. A need is apparent for some auxiliary slide mechanism allowing simple raising and lowering of the headrest relative to the chair back which may be accomplished either by the operator or the patient/user of the chair.
Additionally, it has been found that many headrests and headrest adjustment mechanisms are so thick, when measured front-to-back, that when the chair, headrest and patient are laid back to a nearly horizontal position, with the patient's head preferably as close to the operator's (dentist or hygienist) lap as possible, the patient's head still is elevated some distance above the operator's lap. This can produce an inconvenient working position for the operator, requiring that their hands and wrists be placed in undesirable positions. It has been found that the lower the patient's head may be relative to the operator's lap, the more desirable the angle for the operator's hands and wrists. Thus, a thinner mechanism and headrest are desirable to allow such.
Thus it is desirable to provide headrest adjustment mechanism which can be worked through a covering bag, is easy to clean, is simple to operate, is reduced to as small a package as possible to provide good positioning of the patient for the operator to work on, and is operated with a single hand operated manual actuator which requires a minimal amount of force to release the headrest from a lock up position to permit adjustment, yet when the actuator is released positive locking for the headrest in a desired orientation is provided.